1. Field of the Invention
The present invention relates to hydraulic fluid systems in general, such as hydraulic regenerative drive systems, and, more particularly, to a service module for a hydraulic fluid system including a hydraulic service module containing at least one hydraulic fluid accumulator.
2. Description of the Prior Art
In conventional integrated pressurized fluid systems the recovered energy is normally accumulated in flywheel accumulators, in electrochemical batteries or in hydraulic fluid accumulators. The latter are of known technology and, in comparison with the other recovery and accumulation arrangements, they are more flexible in use, notably in connection with a vehicular transmission to which they are connected. On the other hand they remain less efficient in terms of mass and volume and consequently raise serious problems for fitting onto motor vehicles. In addition to penalizing the energy savings obtained, these problems of dead weight and bulk lead to high costs linked either with the hydraulic fluid accumulator itself or, mainly, with the modifications that have to be made to the vehicle to fit the accumulator. The result is that the motor vehicles equipped with the hydraulic fluid accumulator are no longer standard in any way and are therefore much more expensive to produce and maintain and that, furthermore, the equipment used for this installation cannot be transposed to another vehicle or modulated in size, which increases the overall cost of such an installation.
Furthermore, as parts of a hydraulic regenerative drive system being incorporated into a motor vehicle, such as a cargo box trucks, it is necessary to package various system components onto the vehicle. In the existing vehicles equipped with the hydraulic regenerative drive system, the necessary system components are distributed around the vehicle in a fashion that would be unacceptable in a production system. In particular, the existing vehicles have components mounted in the cargo area and in other areas which required that the existing components be relocated. Moreover, the primary design challenge lies in the fact that some motor vehicles have several variants. It is required to design a system packaging configuration which would be common to all variants, would not violate the existing vehicle envelope, and would not intrude upon the cargo area of the motor vehicle.
Accordingly, it is the intent of this invention to overcome these shortcomings of the prior art by providing a compact service module including a pressure vessel assembly combining all the accumulation functions and capable of being fitted without any substantial modification to various types of pressurized fluid systems, including standard motor vehicles equipped with hydraulic regenerative drive system intended for charging and discharging the hydraulic fluid accumulators.